Eucalyptus cinerea seed extract alleviates bleomycin-induced pulmonary fibrosis in rats by targeting oxidative stress, inflammation, and immune pathways.

Pulmonary fibrosis (PF) is a devastating, progressive interstitial lung disease with limited treatment options and a poor prognosis. Current therapies, such as pirfenidone and nintedanib, often provide only modest benefits, primarily slowing disease progression rather than reversing it. A critical gap exists in therapies that can effectively address the multifactorial pathology of PF, which involves chronic inflammation, excessive oxidative stress, and dysregulated immune responses. Traditional medicine has long utilized natural compounds for their anti-inflammatory and antioxidant properties, suggesting a potential for novel, multi-targeted therapeutic approaches from botanical sources to modulate these complex pathways.

Researchers investigated the curative potential of an aqueous extract from Eucalyptus cinerea seeds (ECAE) against bleomycin (BLEO)-induced sub-acute experimental pulmonary fibrosis in male rats. The study first performed a phytochemical analysis of ECAE, identifying 7 phenolic compounds, including 3 phenolic acids, 3 flavonoids, and 1 tannin. For the in vivo assay, rats were induced with PF via intratracheal instillation of BLEO. Subsequently, they received ECAE treatment. The primary endpoints included assessment of lung lesions and histopathological alterations. Additionally, the study measured plasma and pulmonary lipid peroxidation, levels of enzymatic and non-enzymatic antioxidants, intracellular hydrogen peroxide, and calcium levels. Anti-inflammatory and immunomodulatory properties were also evaluated.

ECAE treatment significantly reduced BLEO-induced lung lesions and improved histopathological alterations in the rat model of pulmonary fibrosis. The extract effectively attenuated both plasma and pulmonary lipid peroxidation, a key indicator of oxidative damage, and reversed the depletion of crucial enzymatic and non-enzymatic antioxidants. This suggests a robust antioxidant defense mechanism. Furthermore, intratracheal instillation of BLEO significantly increased intracellular hydrogen peroxide and calcium levels, which are critical mediators of cellular stress and damage. > ECAE treatment successfully reversed all these intracellular mediator perturbations, restoring cellular homeostasis. Beyond its antioxidant effects, ECAE also exhibited potent anti-inflammatory and immunomodulatory properties, indicating a broad-spectrum action against the complex pathology of PF. These findings collectively highlight ECAE's ability to mitigate multiple facets of bleomycin-induced lung injury.